Many Canadians do not realize they have become common-law for tax purposes until a benefit changes or the CRA asks questions — for example, the GST/HST credit is recalculated using combined family income once you qualify. The tax definition of common-law is not based on whether you call each other spouses. It depends on the CRA’s tests.
The basic CRA test
You are usually common-law for tax purposes if either of these is true:
| Test | Rule |
|---|---|
| 12-month rule | You have lived together in a conjugal relationship for 12 continuous months |
| Child rule | You share a child by birth or adoption, or one partner has custody and the other supports the child |
If you meet either test, CRA expects you to report common-law status.
What counts as living together?
Living together does not mean you are physically under the same roof every night without exception. Temporary absences usually do not break the count.
Examples that often do not reset the 12-month period:
- work travel
- short-term schooling elsewhere
- visiting family
- temporary medical or family-related absences
What is a conjugal relationship?
CRA looks at the relationship as a whole.
Common indicators include:
- shared home or routine living arrangement
- shared finances or household responsibilities
- presenting yourselves socially as a couple
- emotional and economic interdependence
Why this matters for taxes and benefits
Once CRA treats you as common-law, certain benefits and credits are recalculated using combined family income, including programs such as the GST credit and the child care expense deduction.
| Program | Effect |
|---|---|
| GST/HST credit | Based on combined income |
| Canada Child Benefit | Based on combined family income |
| Spousal amount | May become relevant |
| Medical and donation claims | Pooling options may improve tax result |
That is why some people see benefits drop after becoming common-law.
Common situations people ask about
| Situation | Likely Tax Answer |
|---|---|
| Living together 8 months, no child | Usually not common-law yet |
| Living together 12+ months | Usually yes |
| Have a child together after 4 months | Often yes sooner |
| Keep separate bank accounts | Can still be common-law |
| One partner travels often for work | Still may be common-law |
What if you do not update CRA?
That can cause problems.
You may face:
- benefit overpayments
- reassessments
- repayment demands
- possible interest charges
The issue is usually not that CRA is looking for a label. It is that the wrong marital status changes benefit calculations.
Common-law for tax vs provincial family law
Tax treatment and family-law rights are not always the same.
| Topic | Tax Rules | Family Property Rules |
|---|---|---|
| Common-law definition | Federal CRA rules | Provincial law varies |
| Property division on breakup | Not a CRA issue | Depends on province |
If you want the broader legal and financial picture, see common-law relationships in Canada.
Bottom line
You are likely common-law for tax purposes if you have lived together in a conjugal relationship for 12 continuous months or you meet the child-related rule sooner. Once that happens, CRA expects your marital status to be updated, and your benefits and tax calculations may change.
Benefits affected by common-law status
Once CRA recognizes you as common-law, these benefits and credits recalculate using combined family net income instead of your individual income:
| Benefit | How it changes |
|---|---|
| GST/HST credit | One payment per couple (not two); amount based on combined income — may increase or decrease depending on incomes |
| Canada Child Benefit (CCB) | Calculated on combined family net income; usually decreases for higher-income couples |
| Canada Workers Benefit (CWB) | Switches to family CWB calculation; thresholds are higher but so is phase-out ceiling |
| Spousal tax credit | You can claim a non-refundable spousal amount if your partner’s income is below $15,705 |
| Medical expense credit | You can pool medical expenses and claim them on the higher-income partner’s return |
| RRSP spousal contributions | You can contribute to a spousal RRSP using your own contribution room |
| Ontario Trillium Benefit / provincial credits | Most provincial income-tested credits also use combined income |
How to update your marital status with CRA
You are legally required to notify CRA when your marital status changes. Use one of these methods:
- Online: Log into CRA My Account → Profile → Update marital status
- Form RC65: Download and mail CRA Form RC65 (Marital Status Change)
- Tax return: Update the marital status field on your T1 return when you file
- My Account app: Status changes can be made through the CRA My Account mobile app
You should notify CRA by the end of the month following the month the change occurred. For example, if you moved in together in June 2024 and completed 12 months in June 2025, notify CRA by the end of July 2025.
If you were already receiving benefits as a single person, CRA will recalculate from the date of the status change. In some cases, you may have received more benefit than you were entitled to — CRA will recover this through future benefit reductions or by requesting repayment.
Separating after common-law: tax implications
If you separate after being recognized as common-law, you revert to single status for tax purposes once you have been separated for at least 90 days. During those 90 days, you are still considered common-law.
After separation:
- Update your marital status with CRA
- Benefits recalculate on individual income
- Spousal RRSP contributions stop (no new contributions, but the account remains)
- If you have children, determine who claims the CCB (usually the primary caregiver)
- Separation also triggers a deemed disposition for some property — consult a tax professional if significant assets are involved